Performance of Linear Vibration Energy Harvesters under Broadband Vibrations with Multiple Frequency Peaks

This paper studies the performance of linear Vibration Energy Harvesters (VEH) under broadband vibrations with multiple frequency peaks. The output power of both electromagnetic and piezoelectric linear VEH is determined when excited by a single frequency excitation and when excited by two frequency peaks, one at resonance and the other at a different frequency (defined as the interference frequency). Experimentally, it was found that when a linear VEH is excited by two-peak vibrations, its output power is lower than in the case of the single frequency excitation. Furthermore, the larger the amplitude at the interference frequencies, the lower the output power of the VEH. Also, for the same interference peak amplitudes, the further the interference frequency is from the resonant frequency, the lower the output power is. These results suggest that when designing a linear VEH for multiple-peak broadband vibrations, the VEH should be matched to the lowest peak frequency and that pure sinusoidal excitation should be avoided when laboratory testing VEH for use in applications with multiple frequencies.